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The Single UNIX &reg; Specification, Version 2<br>
Copyright &copy; 1997 The Open Group

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<h4><a name = "tag_000_007_964">&nbsp;</a>NAME</h4><blockquote>
perror - write error messages to standard error
</blockquote><h4><a name = "tag_000_007_965">&nbsp;</a>SYNOPSIS</h4><blockquote>
<pre><code>

#include &lt;<a href="stdio.h.html">stdio.h</a>&gt;

void perror(const char *<i>s</i>);
</code>
</pre>
</blockquote><h4><a name = "tag_000_007_966">&nbsp;</a>DESCRIPTION</h4><blockquote>
The
<i>perror()</i>
function maps the error number accessed through the symbol
<i>errno</i>
to a language-dependent error message, which is written to the
standard error stream as follows: first (if
<i>s</i>
is not a null pointer and the character pointed to by
<i>s</i>
is not the null byte), the string pointed to by
<i>s</i>
followed by a colon and a space character;
then an error message string followed
by a newline character.  The contents of the error message strings
are the same as those returned by
<i><a href="strerror.html">strerror()</a></i>
with argument
<i>errno</i>.
<p>
The
<i>perror()</i>
function will mark the file associated with the standard
error stream as having been written
(<i>st_ctime</i>,
<i>st_mtime</i>
marked for update) at some time between its successful completion and
<i><a href="exit.html">exit()</a></i>,
<i><a href="abort.html">abort()</a></i>,
or the completion of
<i><a href="fflush.html">fflush()</a></i>
or
<i><a href="fclose.html">fclose()</a></i>
on
<i>stderr</i>.
<p>
The
<i>perror()</i>
function does not change the orientation of the standard error stream.
</blockquote><h4><a name = "tag_000_007_967">&nbsp;</a>RETURN VALUE</h4><blockquote>
The
<i>perror()</i>
function returns no value.
</blockquote><h4><a name = "tag_000_007_968">&nbsp;</a>ERRORS</h4><blockquote>
No errors are defined.
</blockquote><h4><a name = "tag_000_007_969">&nbsp;</a>EXAMPLES</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_007_970">&nbsp;</a>APPLICATION USAGE</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_007_971">&nbsp;</a>FUTURE DIRECTIONS</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_007_972">&nbsp;</a>SEE ALSO</h4><blockquote>
<i><a href="strerror.html">strerror()</a></i>,
<i><a href="stdio.h.html">&lt;stdio.h&gt;</a></i>.
</blockquote><h4>DERIVATION</h4><blockquote>
Derived from Issue 1 of the SVID.
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UNIX &reg; is a registered Trademark of The Open Group.<br>
Copyright &copy; 1997 The Open Group
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